The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to embodiments of the claimed inventions.
Plasma Enhanced Chemical Vapor Deposition (PECVD) and PECVD tools enable a process by which thin films are deposited from a gas state (vapor) to a solid state onto a substrate by chemical reactions which occur after creation of a plasma of the reacting gases. The plasma is generally created by RF (AC) frequency or DC discharge between two electrodes, the space between which is filled with the reacting gases.
Dielectric films such as Silicon-Nitride and Silicon-Dioxide are used in the production of silicon solar cells. It is desirable, for the purpose of creating selective, well defined structures and metallizations to pattern these films on the surface of alkaline textured silicon. An industrially feasible method for patterning these films is to remove them with a laser. Presently known and conventional laser removal processes unfortunately causes damage to the surface of the silicon. Such processes are the best known techniques in the current state of the art and therefore, a balance is made between the extent of film removal via laser and resulting damage to the underlying silicon. For instance, greater removal of the layers exposes more silicon, and thus increases efficiency of the cell, whilst simultaneously causing increasing amounts of damage to the silicon, thus reducing efficiency of the cell.
Removal of the films by any means without causing damage or by causing less damage to the underlying silicon therefore improves efficiency of the cell, resulting in greater power generation, assuming equal amounts of the film are removed.
Laboratory demonstrated chemical techniques (photolithography) have been demonstrated to remove greater amounts of the thin layers without the use of lasers thus resulting in little to no damage to the underlying silicon which in turn results in optimal efficiency and power generation, however, such chemical methods do not scale to industrial manufacturing at costs that are feasible for solar production, and therefore, have proven undesirable for commercial manufacturers which must compete with lower-cost providers of silicon cells to the marketplace.
A lower cost laser removal process which provides sufficient layer removal and reduces damage to the underlying silicon is needed.
The present state of the art may therefore benefit from systems and methods for implementing damage-and-resist-free laser patterning of dielectric films on textured silicon as is described herein.